title: Time to positivity as prognostic tool in patients with Pseudomonas aeruginosa bloodstream infection.
abstract: OBJECTIVE
  The time to positivity (TTP), measured as the time span between the start of incubation and the alert signal from the blood culture device, has been described as useful tool of prognosis in patients suffering from blood stream infection with Staphylococcus aureus, Escherichia coli and Klebsiella pneumonia. The present study investigates the relationship between TTP and in-hospital mortality in patients with monomicrobial Pseudomonas aeruginosa blood stream infection (PA-BSI).
  
  
  METHODS
  From 2006 until 2012 a retrospective cohort study was undertaken in 3 hospitals in the region surrounding Tübingen, Germany. Seventy-four patients with monomicrobial PA-BSI were studied. TTP and clinical parameters were determined and analyzed by receiver operating characteristic (ROC) analysis and Cox regression.
  
  
  RESULTS
  The in-hospital mortality of our clinical cohort was 33.78%. In multivariate Cox regression, a TTP ≤ 18 h proved to be independently associated with mortality (HR 3.83, P = 0.012) along with SAPS II score (HR 1.04, P = 0.006), cardiac disease (HR 0.33, P = 0.008) and appropriate definitive antimicrobial treatment (HR 0.21, P = 0.013).
  
  
  CONCLUSIONS
  TTP is an easy-to-measure laboratory tool for prognosis in patients with monomicrobial PA-BSI, providing useful information in addition to clinical parameters.
authors.affiliation: Institute of Medical Microbiology and Hygiene, University of Tübingen, Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Willmann
authors.forename: Ines
authors.initials: I
authors.lastname: Kuebart
authors.forename: Wichard
authors.initials: W
authors.lastname: Vogel
authors.forename: Ingo
authors.initials: I
authors.lastname: Flesch
authors.forename: Uwe
authors.initials: U
authors.lastname: Markert
authors.forename: Matthias
authors.initials: M
authors.lastname: Marschal
authors.forename: Klaus
authors.initials: K
authors.lastname: Schröppel
authors.forename: Ingo B
authors.initials: IB
authors.lastname: Autenrieth
authors.forename: Florian
authors.initials: F
authors.lastname: Hölzl
authors.forename: Silke
authors.initials: S
authors.lastname: Peter
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D019540:Area Under Curve; D016470:Bacteremia / Q000175:diagnosis / Q000382:microbiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011552:Pseudomonas Infections / Q000175:diagnosis / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification*; D012189:Retrospective Studies
keywords: Bacteremia; Blood stream infection; Cox regression; Mortality; Prognosis; Pseudomonas aeruginosa; ROC analysis; Risk factor; Time to positivity